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Analog Devices Inc./Maxim Integrated MAX6725KAYDD3-T
- Part No.:
- MAX6725KAYDD3-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6725KAYDD3-T.pdf
- Description:
- IC SUPERVISOR 3 CHANNEL SOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:2,500
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Product details
Overview
The MAX6725KAYDD3-T from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in an 8-pin SOT23 package, monitoring VCC1 (4.625V threshold), VCC2 (3.075V threshold), and an externally adjustable RSTIN input (626.5mV reference). It provides active-low open-drain RST and RST2 outputs, manual reset input, watchdog timer with 35s startup/1.12s normal timeout, and operates from -40°C to +85°C. It ensures reliable system reset in multivoltage embedded power management applications.
For engineers reviewing the MAX6725KAYDD3-T datasheet, MAX6725KAYDD3-T pinout, MAX6725KAYDD3-T application, or MAX6725KAYDD3-T equivalent, key selection criteria include dual independent reset outputs, factory-trimmed dual voltage thresholds, RSTIN-adjustable third-voltage monitoring down to 0.62V, guaranteed reset validity at VCC ≥ 0.8V, and SOT23-8 footprint compatibility with industrial-grade temperature operation.
Technical Context
The MAX6725KAYDD3-T implements a dual-threshold analog comparator architecture for VCC1 and VCC2, each with ±0.5% hysteresis and 20ppm/°C tempco, plus a high-impedance RSTIN input referenced to a 626.5mV internal bandgap. Its reset logic asserts RST/RST2 low when any monitored supply falls below its threshold or MR is pulled low, maintaining assertion for a fixed 210ms (min) timeout after recovery.
It integrates a dual-mode watchdog timer: a 35s (min) initial timeout after power-up/manual reset enables full system boot, followed by a 1.12s (min) normal timeout triggered by missing WDI edges. The device guarantees correct reset output state with VCC1 or VCC2 ≥ 0.8V and draws only 14µA typical supply current at 3.6V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Threshold | 4.625V (factory-trimmed, ±125mV tolerance) - sets primary supply brownout detection point for 5V rails |
| VCC2 Threshold | 3.075V (factory-trimmed, ±75mV tolerance) - sets secondary supply brownout detection for 3.3V rails |
| RSTIN Reference | 626.5mV (±15.5mV) - enables external resistor-divider to monitor third supply as low as 0.62V |
| Reset Timeout | 210ms (min) - ensures µP reset pulse meets minimum hold time requirements across temperature |
| Watchdog Timeout | 1.12s (min) normal mode - detects software hangs without requiring frequent I/O toggling |
| Supply Current | 14µA (typ at 3.6V) - minimizes quiescent power in battery-backed or always-on systems |
| Operating Temp | -40°C to +85°C - supports industrial and telecom equipment deployment without derating |
Pinout & Package
Package: 8-pin SOT23-8, surface-mount, lead-free compatible (-T suffix), 1.6mm × 2.9mm footprint, 1.1mm height.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-low open-drain reset output referenced to VCC1; requires external pullup for logic-high level |
| 2 | GND | System ground reference for all internal comparators and logic |
| 3 | MR | Active-low manual reset input with 50kΩ internal pullup to VCC1; debounced by 100ns glitch rejection |
| 4 | RST2 | Active-low open-drain reset output referenced to VCC2; independent timing but same assertion logic as RST |
| 5 | VCC2 | Secondary supply input (0.9V–3.3V range); powers internal VCC2 comparator and RST2 driver |
| 6 | VCC1 | Primary supply input (1.8V–5.0V range); powers core logic, VCC1 comparator, and RST driver |
| 7 | RSTIN/PFI | Shared pin: selectable as adjustable reset monitor (RSTIN) or power-fail input (PFI); 626.5mV internal reference |
| 8 | WDI | Watchdog input; rising/falling edge clears 1.12s timeout; long idle (>35s) triggers initial watchdog mode |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent reset outputs | RST (VCC1-referenced) and RST2 (VCC2-referenced) enable separate reset control for I/O and core domains |
| Externally adjustable third-voltage monitor | RSTIN pin with 626.5mV reference allows precise monitoring of auxiliary rails (e.g., 1.2V, 1.8V) via resistor divider |
| Dual-mode watchdog timer | 35s startup timeout prevents false resets during boot; 1.12s normal timeout ensures rapid hang detection post-initialization |
| Guaranteed reset validity at low VCC | Operates correctly with VCC1 or VCC2 ≥ 0.8V - critical for brownout recovery in unregulated supplies |
| Immunity to short VCC transients | Withstands ≤20µs negative glitches at 100mV overdrive - eliminates spurious resets from switching noise |
Applications
| Server Power Sequencing | Industrial PLC Controller |
|---|---|
Use Scenario: Coordinating power-up sequence of CPU, memory, and I/O rails in 1U rack servers with multiple DC-DC converters. IC Role / Device Role / Timing Role: Monitors 5V (VCC1), 3.3V (VCC2), and 1.2V core (via RSTIN) to assert synchronized reset until all rails stabilize. Use Value: Prevents CPU lockup during asymmetric rail ramp-up by enforcing 210ms reset hold time after last rail crosses threshold. | Use Scenario: Ensuring deterministic restart after undervoltage events in programmable logic controller modules deployed in factory automation. IC Role / Device Role / Timing Role: Supervises main 24V DC input (VCC1), isolated 5V logic rail (VCC2), and FPGA configuration voltage (RSTIN) with manual reset override. Use Value: Guarantees valid reset assertion even if 24V rail sags to 0.8V, enabling fail-safe recovery without external supervision. |
| Telecom Line Card | Portable Medical Monitor |
Use Scenario: Managing power integrity in carrier-grade line cards with hot-swap capability and redundant power inputs. IC Role / Device Role / Timing Role: Uses RST and RST2 to independently reset processor subsystem and PHY interface on separate voltage domains. Use Value: Eliminates need for two discrete supervisors - reduces BOM count and PCB area while maintaining domain isolation. | Use Scenario: Maintaining safe operation in battery-powered ECG monitors where supply voltage drops gradually during discharge. IC Role / Device Role / Timing Role: Monitors main 3.3V rail (VCC1), backup 1.8V SRAM supply (VCC2), and battery voltage (RSTIN) to trigger graceful shutdown before data loss. Use Value: 14µA quiescent current extends battery life; 626.5mV RSTIN reference enables accurate low-battery detection down to 2.5V. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6726KAyDD3-T | Push-pull RST output (vs. open-drain on MAX6725); identical thresholds, timeout, and pinout | Eliminates need for external pullup resistor on RST; unsuitable for bidirectional µP reset pins without series resistor | Select MAX6726KAyDD3-T when driving CMOS inputs directly or when board space prohibits pullup placement |
| TPS3808G33DBVR | Single-supply monitor (3.3V only); no RST2, no RSTIN, no watchdog; 200ms timeout; SOT23-6 package | Lacks triple-monitoring, independent reset outputs, and watchdog - suitable only for simple single-rail systems | Choose TPS3808G33DBVR only for cost-sensitive, space-constrained designs with no requirement for auxiliary voltage monitoring or watchdog functionality |
Compared with MAX6725KAYDD3-T, MAX6726KAyDD3-T offers push-pull RST for direct drive but sacrifices open-drain flexibility, while TPS3808G33DBVR reduces feature set and package size at the cost of losing triple-voltage supervision, dual reset outputs, and watchdog capability - making it a functional subset rather than a drop-in replacement.
Availability
MAX6725KAYDD3-T is available at Aetrix Electronics and suitable for server power sequencing, industrial PLC controllers, telecom line cards, and portable medical monitors requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for MAX6725KAYDD3-T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) designs precision analog and mixed-signal ICs for power management, sensing, and connectivity in demanding industrial, automotive, and communications applications.
The MAX6715–MAX6729 family delivers ultra-low-voltage, multi-rail supervisory circuits optimized for space-constrained embedded systems requiring reliable power-up sequencing, brownout protection, and watchdog safety monitoring.
FAQ
What voltage thresholds does the MAX6725KAYDD3-T monitor?
The MAX6725KAYDD3-T monitors VCC1 at 4.625V (±125mV), VCC2 at 3.075V (±75mV), and supports an externally adjustable third voltage via the RSTIN pin using a 626.5mV internal reference. These factory-trimmed thresholds are confirmed in the Reset Voltage Threshold Suffix Guide and Electrical Characteristics table of the official datasheet. The MAX6725KAYDD3-T does not support user-programmable thresholds - all values are fixed at manufacture.
Does the MAX6725KAYDD3-T provide both active-low and active-high reset outputs?
No, the MAX6725KAYDD3-T provides two active-low open-drain reset outputs: RST (referenced to VCC1) and RST2 (referenced to VCC2). It does not include an active-high reset output. The device's Selector Guide explicitly lists MAX6725 as having "1" open-drain RST and "1" open-drain RST2, with no push-pull or active-high variants in this specific part number. For active-high functionality, consider MAX6726KAyDD3-T.
How is the 210ms reset timeout period implemented in the MAX6725KAYDD3-T?
The MAX6725KAYDD3-T implements a fixed 210ms (minimum) reset timeout using an internal RC oscillator calibrated during production - no external components are required. This timeout begins when all monitored supplies (VCC1, VCC2, RSTIN) rise above their respective thresholds, MR returns high, or watchdog activity resumes. The value is specified in the Reset Timeout Period Suffix Guide as "D3" and verified across -40°C to +85°C in the Electrical Characteristics table.
Can the MAX6725KAYDD3-T monitor a negative supply voltage?
Yes, the MAX6725KAYDD3-T can monitor a negative supply using the RSTIN/PFI pin with an external resistor network as shown in Figure 3b of the datasheet. When configured as PFI, the comparator's noninverting input detects when the divided negative rail falls below 626.5mV, causing PFO to go high. Accuracy depends on resistor tolerance, PFI input current (±25nA), and VCC stability. The MAX6725KAYDD3-T itself must be powered by positive VCC1/VCC2 supplies.
What is the function of the WDI pin on the MAX6725KAYDD3-T?
The WDI (Watchdog Input) pin on the MAX6725KAYDD3-T monitors microprocessor activity: a rising or falling edge clears the 1.12s (min) normal watchdog timeout, while absence of edges for >35s triggers the long-startup mode. After any reset event, the watchdog enters 35s startup mode, then transitions to 1.12s normal mode upon first valid WDI transition. This dual-mode behavior prevents false timeouts during boot while ensuring rapid hang detection during steady-state operation - a core feature of the MAX6725KAYDD3-T.
MAX6725KAYDD3-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SOT-23-8
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Multi-Voltage Supervisor
- Number of Voltages Monitored:
- 3
- Voltage - Threshold:
- 0.788V, 2.188V, Adj
- Output:
- Open Drain, Open Drain
- Reset:
- Active High/Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-8
MAX6725KAYDD3-T FAQ
1.How can I place an order for MAX6725KAYDD3-T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6725KAYDD3-T on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX6725KAYDD3-T reliable?
The price and inventory of MAX6725KAYDD3-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6725KAYDD3-T is usually 5 days.
3.What payment methods are accepted for MAX6725KAYDD3-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6725KAYDD3-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6725KAYDD3-T?
MAX6725KAYDD3-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6725KAYDD3-T order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX6725KAYDD3-T?
For technical support, including MAX6725KAYDD3-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6725KAYDD3-T requirements.
6.How does Aetrix verify that MAX6725KAYDD3-T is sourced from the original manufacturer or authorized distributors?
All MAX6725KAYDD3-T products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX6725KAYDD3-T meets industry standards.
7.What is the process for return or replacement of MAX6725KAYDD3-T?
All MAX6725KAYDD3-T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6725KAYDD3-T, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX6725KAYDD3-T part is unused and in its original packaging.
Return procedure for MAX6725KAYDD3-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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